The present investigation is aimed at the development of new radiopharmaceuticals for renal function studies and imaging. At present there are available two groups of radioactive materials for use in kidney studies. One group, although well suited for renal function studies, is not particularly suited for imaging because of the label with an isotope of relatively poor physical characteristics. The second group of compounds, although well suited for imaging, has the disadvantage of not being identified with any clear-cut renal function parameter. It is the aim of this project to develop a more universally applicable group of radioactive compounds which may be used to measure glomerular filtration rate and/or effective renal plasma flow and which is labeled with desirable isotopes of good physical characteristics. Such compounds will permit a combination of good studies of renal function in conjunction with renal imaging providing both functional and morphologic information in a single study. In the course of these investigations we have currently begun to investigate the use of copper as a reducing agent which has the potential of altering the biologic characteristics of compounds currently available and opens a new path to synthesis of radiopharmaceuticals which may yield compounds of the type we are seeking in this project. BIBLIOGRAPHIC REFERENCE: Technetium-99m-Cu-HEDSPA - A New Skeletal Imaging Agent. L.R. Chervu, Q. Goyal and M.D. Blaufox. J. Nucl. Med. 16:520, 1975.